Filter and filter cartridge with peripheral stop for filtering liquids circulating in an engine or in a hydraulic equipment

ABSTRACT

The invention concerns a filter for liquid circulating in an engine unit or in hydraulic equipment including a tank ( 1 ) cooperating with a closure element ( 2 ) with a filtering cartridge ( 3 ) inserted in the tank ( 1 ) and adjusted therein by threadedly engaging the closure element ( 2 ) with the tank ( 1 ). The cartridge ( 3 ) includes a filtering material ( 4 ) having at one of its ends a first flange ( 5 ) and at the other of its ends a second flange ( 6 ) that includes a peripheral seal ( 8 ) designed to be sealingly clamped between an end of the tank and the closure element ( 2 ) when the tank ( 1 ) is threadedly with the closure element ( 2 ). The invention is characterized in that it includes at least one element forming a stop ( 9, 91 ) provided on the second flange ( 6 ) and/or on the closure element ( 2 ) and/or on the tank ( 1 ), the element forming a stop ( 9,91 ) being designed to control clamping of the peripheral seal ( 8 ) with the closure element ( 2 ).

The field of the invention is that of the filtration of a liquid,notably oil, fuel or cooling liquid, circulating in an engine, inparticular, in a thermal engine or in a piece of hydraulic equipment.

More precisely, the invention relates to a filter of the type comprisinga tank that receives a filter cartridge and which can be closed by aclosure element, said filter cartridge being detachable and being ableto be replaced after a certain using time. This type of cartridgegenerally has a tubular shape and defines, within the filter, anupstream filtering compartment and a downstream filtering compartment.There are filters in which the upstream filtering compartment is formedbetween the internal wall of the tank and the outside of the cartridgewhile the downstream filtering compartment is constituted by theinternal chamber of the cartridge while, conversely, in other types offilters, it is the internal chamber of the cartridge that constitutesthe upstream filtering compartment, the downstream filtering compartmentbeing formed between the internal wall of the tank and the external wallof the cartridge.

In certain types of engine, the tank of the filter is integrated withthe engine block and closed by a cover which can be removed in order toaccess the filtering cartridge, while in other types of engine, it isthe filter tank which is detachable and which can be screwed onto a“filter head” integrated with the engine block. In this description, onetherefore understands the term “closure element” as being either thecover mentioned above or the filter head.

When the cartridge positioned in the tank is worn out, that is to saywhen the filtering element no longer fulfils its filtration rolesatisfactorily, according to the case, either the cover is removed orthe tank is separated from the filter head, the used cartridge is takenout of the tank and is replaced by a new cartridge and the cover isreplaced or the tank is replaced against the filter head.

Subsequently, used cartridges are incinerated in such a way that thepolluting organic substances are destroyed and the inorganic pollutingmaterials are concentrated. With the aim of optimizing such anoperation, it has been proposed in the state of the technology that theyare made from “green” materials which can be incinerated given a minimumof polluting materials. Such “green” cartridges have a mono-layered ormulti-layered filtering material (also called a “medium” in the languageof men skilled in the art) made up, for example, of paper, cardboard,fabric or woven or non-woven fibers (or of a mixture or asuperimposition of such materials, one layer of which can be a supportlayer), most commonly folded into a star, and two end flanges made of anon-metallic material which preferably are not connected to one anotherby any rigid link other than the medium, which then facilitates theirincineration, the lack of any rigid member then allowing one to reducenotably the proportion of plastic material necessary for the manufactureof such cartridges. In the case where a support material is present,this can be rigid or of chosen flexibility.

The operation of this kind of filter is as follows: the liquid to befiltered (for example oil) is admitted through an inlet orifice, itarrives in the upstream filtering compartment, passes through afiltering element of the cartridge which retains the particles found insuspension in the liquid, then the liquid filtered in this way passesinto the downstream filtering compartment and leaves through an outletorifice.

In a conventional way, the sealing of the tank with the closure elementis provided by a gasket which must be positioned by the user. So as tofacilitate the placement of the cartridge and to avoid handling such agasket, it has also been proposed in the state of the technology tointegrate such a gasket with the periphery of one of the flanges of thecartridge itself, this flange part being blocked between the cover andthe tank during placement.

One of the disadvantages associated with the use of this kind of filteris apparent during the operation of clamping the tank with the closureelement.

This clamping can, according to the various types of known filters, becarried out notably by directly screwing the tank with the closureelement or by bolting it. In the majority of filters, it is verydifficult for the user to obtain good clamping, that is to say clampingthat is sufficiently strong to enable one to guarantee the seal providedby the gasket provided between the tank and the closure element but nottoo strong so that the properties of the gasket under considerationdeteriorate or that the closure element or the tank is deformed ordamaged.

Hence as a general rule, the user has a tendency either to tighten thetank and the closure element too much which leads to a reduction in thesealing capability of the filter and as a consequence its life, or tonot tighten it sufficiently which leads to leaks, the gasket then onlypartially fulfilling its function.

In the filters that use several bolts to fix the closure element ontothe tank, the clamping obtained is generally not well distributedbetween the various bolts, which increases the risks of leaks or ofdeterioration of the gasket. This problem is increased because thisclamping operation must be carried out using a tool which makes it evenmore difficult to judge the degree of clamping.

In order to respond to this problem, it has already been proposed in thestate of the technology to provide a gasket between the closure elementand the tank. Such a solution has however the disadvantage of using agasket which is not integral with the filter cartridge and also that ofimplying a contact between the metal of the closure element and themetal of the tank, such a contact possibly leading to seizing. Finally,such a solution necessitates a high clamping torque.

The objective of this invention is to describe a technical solution thatallows one to use a seal integrated with a second flange of the filtercartridge and enables one to provide a homogeneous and straightforwardclamping of the closure element with the tank, using a moderatetightening torque that can be provided manually.

This objective is achieved by the invention which relates to a filterfor a liquid circulating in an engine block or in a piece of hydraulicequipment that includes a tank co-operating with a closure element and afilter cartridge inserted into said tank and locked into it by clampingsaid closure element with said tank, said cartridge being of the typethat includes a filtering material having at one of its ends a firstflange and at the other of its ends a second flange the peripheral partof which is designed to be blocked between said tank and said closureelement when said tank is clamped with said closure element,

characterized in that it includes at least one element forming a stopprovided on said second flange and/or said closure element and/or onsaid tank, said element forming a stop being designed to control saidclamping of said tank with said closure element.

Such a stopping element allows the user to know at what moment the idealclamping of the closure element with the tank has been achieved. Itshould be noted that such clamping will generally be carried out byscrewing, this screwing taking place according to case, by screwing theclosure element (cover) onto the tank, when this is integral with thefilter head or by screwing the tank onto the filter head which thenconstitutes the closure element. In the first case, the invention couldalso be implemented when the cover is bolted onto the tank.

Furthermore, such a stopping element allows one to use a moderatetightening torque that permits effective clamping by hand and produces aclear sensation of clamping. This stopping element therefore enables oneto avoid all the problems associated with too tight a clamping orinsufficient clamping that are mentioned above.

It could also be envisaged to create the stopping element according tothe invention on one of the flanges of the filter cartridge, forexample, using one or more elements that project from its surface orforming this stopping element using at least one element that projectsfrom the closure element and/or from the tank (at the edge of itsopening).

Hence, according to a first variant, said element forming a stop isprovided on said peripheral part of said second flange of said filtercartridge.

According to another variant, said element forming a stop comprises atleast one element that projects from said closure element and/or fromsaid tank (at the edge of its opening).

It will be noted that these two variants could be combined, it beingpossible for one of the elements to project from a flange of the filtercartridge and the other from the closure element or from the tank.

According to a preferred variant of the invention, said peripheral partof said second flange is provided with an integral seal. Such anintegral seal can, for example, cover both sides of the edge of theperipheral part of the second flange. Such a type of seal has theadvantage of being present on the cartridge and hence of facilitatingthe positioning and the changing of it, no additional manipulation ofthe seal being necessary for the user.

Also preferably, said stopping element is circular. One could alsoenvisage creating said stop in other shapes, for example in the shape ofseveral circular arcs.

According to one advantageous embodiment of the invention, when thestopping element is provided on the flange, said peripheral part of thisflange comprises at least one first and at least one second projectingelement, the first projecting element on the upper face of saidperipheral part and the second projecting element on the lower face ofsaid peripheral part.

Preferably the first and the second elements are then essentiallyprovided in the same transverse plane.

According to another preferred variant of the invention, said peripheralseal is provided with at least one ridge, the stop and the ridge beingsized in such a way as to control the squeezing of said ridge.Advantageously said ridge has a height which when at rest is greaterthan the height of said stop. Such a ridge enables one to ensure thetightness provided by the seal under all temperature situations mostnotably when it is extremely cold.

Advantageously, said second flange includes a peripheral part, a centralpart fixed to said element of filtering material and a flexible partlinking said central part to said peripheral part. Such a configurationallows one to improve the locking of the cartridge at the bottom of thefilter, notably with the purpose of preventing hyperstatic situationsfor the cartridge which can engender a deterioration of the gaskets ofthe filter, and if the need arises with the purpose of closing off anautomatic emptying orifice provided in the bottom of this tank.

Also advantageously, said filtering material is chosen from the groupmade up of paper, cardboard, fabric, materials made up of woven ornon-woven fibers or by a mixture or a superimposition of these productsand said second flange and said first flange of said cartridge are onlylinked to one another through said element of filtering material. Suchcharacteristics are used in cartridges called “green” cartridges anddescribed above which have the advantage of being easily incinerated.

The invention and the various advantages which it offers, will be moreeasily understood thanks to the description which follows of anon-limitative embodiment of the invention that refers to the drawingsin which:

FIG. 1 represents a first embodiment of an oil filter fitted with afilter cartridge according to the invention;

FIG. 2 represents an enlargement of the circled part A in FIG. 1 showinga section of the peripheral part of the second flange;

FIG. 3 represents a view from above of the second flange (half of itbeing shown, the other half being symmetrical);

FIG. 4 represents a second embodiment of an filter for a liquid coolantfitted with a filter cartridge according to the invention;

FIG. 5 represents another embodiment of the stopping element accordingto the invention.

With reference to FIG. 1, the filter shown comprises four main elements,namely:

a tank 1 intended to be fixed onto a member (not shown) integral with anengine block of a vehicle and provided with an inlet orifice 11 for aliquid to be filtered (in this case an oil), an outlet orifice for afiltered liquid 22 and an emptying orifice 7;

a closure element forming a cover 2 screwed onto the tank 1 duringoperation of the filter;

a tubular filter cartridge 3 including a second flange 6 and a firstflange 5 made of plastic material welded to each of the ends of anelement of filtering material 4 constituted by paper folded into a star;and

a central hollow core 10 provided with openings 101 that communicatewith its internal chamber, said central core being screwed through itsupper end into the cover 2 in such way as to extend along thelongitudinal axis of the filter, said cartridge being positioned aroundthis central core and locked by it.

During operation of the filter, the liquid to be filtered is introducedunder pressure into it through the inlet orifice 11, passes through theupstream filtering compartment 12 defined by the internal wall of thetank 1 and the external wall of the cartridge 3, is filtered by forcedpassage within the filtering material 4 and finds itself in thedownstream filtering compartment 13 defined by the longitudinal port ofthe central core 10, passing through the openings 101, before beingdischarged through the orifice 22.

With reference to FIG. 2, the upper seal of the filter is providedthanks, on the one hand, to a peripheral seal 8 integrated with theperiphery of the second flange 6 of the filter cartridge 3 and, on theother hand, to an internal 0-ring 14 on the inside edge of this sameflange and co-operating with the cover 2.

The lower seal is itself provided by an internal seal 52 and an externalseal 53 on the first flange 5 on either side of a groove 51 in it, saidgroove communicating with the emptying orifice 7 of the tank 1.

As can be seen more clearly when referring to FIG. 3, the second flange6 has three parts, namely a central part 61 directly fixed to theelement of filtering material 4 (for example by bonding, keying orwelding or any other suitable method), a peripheral part 62 thatreceives the integrated seal 8 and a flexible perforated part 63. As ismade clear above, such a flexible flange allows one to improve thelocking of the cartridge to the bottom of the filter, notably with thepurpose of avoiding hyperstatic situations of the cartridge that canengender deterioration of the seals of the filter and in this case withthe purpose of closing off an automatic emptying orifice 7 provided inthe bottom of this tank.

Conforming to this invention and as one can see more clearly in FIG. 2and in FIG. 3, the second flange 6 of the cartridge 3 is fitted with anelement 9 forming a circular stop constituted by a first projectingelement 9 a on the upper face of the flange 6 and by a second projectingelement 9 b on the lower face of this flange. Such a stopping elementallows one to control the tightening of the cover 2 on the tank 1 to afixed and optimum value.

So as to improve the performance of the integrated seal 8, it is fittedwith a ridge constituted by two bulges 8 a, 8 b projecting on eitherside of the seal 8, the height of which at rest is greater than that ofthe stops 9 a, 9 b in such a way as to control the squeezing of the sealbetween the cover and the tank.

Referring to FIG. 4, a second embodiment of a filter for a liquidcoolant fitted with a filter cartridge according to the invention, isrepresented. The filter shown in this Figure only differs essentiallyfrom the filter represented with reference to FIGS. 1 to 3, in thedirection of filtration used (shown by the arrows) which is the reverseof the direction of filtration of the first embodiment. According tothis second embodiment, the liquid to be filtered is introduced underpressure into the filter through the inlet orifice 11 provided at thelower end of a cylinder 21 provided on the inside of the filteringmaterial, passes through the upstream filtering compartment 12 definedby the longitudinal port of the cylinder, is filtered by forced passagewithin the filtering material 4 and finds itself in the downstreamfiltering compartment 13 defined by the internal wall of the tank 1 andthe external wall of the cartridge 3. Conforming to the invention, theupper seal of the filter is provided thanks, on the one hand, to aperipheral seal 8 integrated with the periphery of the second flange 6of the filter cartridge 3 and, on the other hand, to an internal seal 14on the internal edge of this same flange and co-operating with the cover2.

Referring to FIG. 5, another embodiment of the stopping element of afilter according to the invention is described in which this stoppingelement 91 is constituted by one element 9 c projecting from the closureelement forming a cover 2, and by another element 9 d projecting fromthe edge of the opening of the tank 1. The elements 9 c and 9 d permitthe tightening of the cartridge to be controlled at its flange 6.

The embodiments of the invention described here do not have the purposeof reducing the scope of the invention. Numerous modifications could bemade to it without departing from the context of the invention.

What is claimed is:
 1. A filter assembly comprising: means forming anannular tank having an open end defining an opening, means for formingan annular replaceable filtering material insertable in said tank, acircular flange connected to one end of said filtering material means,said flange having an outer diameter sufficiently large to extendoutward beyond said opening of the annular tank at the open end thereof,a peripheral seal element extending around the outer diameter of saidflange, means for connecting said seal element to said flange so thatsaid seal element is retained in place around the periphery of saidflange when said filtering material and flange are out of said annulartank, a closure element releasably securable over the open end of saidtank means for sandwiching said flange between said closure element anda portion of said tank extending radially outwardly beyond said opening,and said peripheral seal element having an axial thickness sufficientlygreat so that the peripheral seal element is compressed when said flangeis sandwiched between said closure member and said portion of theannular tank, and stop means for positively limiting the compression ofsaid peripheral seal element thereby maintaining an effective seal.
 2. Afilter assembly as claimed in claim 1 wherein said stop means isprovided on said flange.
 3. A filter assembly as claimed claim 1 whereinsaid stop means comprises at least one element projecting from saidclosure element forming means to abut said flange.
 4. A filter assemblyas claimed in claim 1 wherein said stop means comprises at least oneelement projecting from said tank forming means to abut said closureelement.
 5. A filter assembly as claimed in claim 1 wherein said flangecomprises a peripheral part, a central part fixed to said filteringmaterial means and a flexible part linking said central part to saidperipheral part.
 6. A filter assembly as claimed in claim 1 wherein saidseal element is annular and has a radially inward facing recess, theperiphery of said flange extending into said recess, thereby retainingsaid seal element in place.
 7. A filter assembly as claimed in claim 6wherein said stop means comprises at least one axially projecting rib onsaid flange.
 8. A filter assembly as claimed in claim 7 wherein saidstop means comprises a pair of continuous circumferentially extendingribs on said flange.
 9. A filter assembly as claimed in claim 8, whereina radially outer periphery of said circumferentially extending ribs abutan inner diameter of said annular seal element.